PERCHLORATE ION SELECTIVE SENSOR BASED ON NEWLY SYNTHESIZED N1, N3 (114-BENZOIMIDAZOLE.241) ISOPHTHALAMIDE RECEPTOR

Abstract

Novel ionophore, NI,N3-di(1H-benzoimidazole-2-ypisophthalamide receptor (I) has been synthesized and characterized by UV, IR and CHN analysis. Polyvinyl chloride (PVC) based membranes of (I) have been prepared and explored as C104 selective sensors. Effect of various plasticizers viz., tris(2-ethylhexyl) phosphate (TEHP), dibutyl phosphate (DBP), dioctyl phosphate (DOP), diethyl phosphate (DEP), tricresyl phosphate (TCP) and a cation excluder, tridodecylmethylammonium chloride (TDDMAC1) was studied in detail and improved performance was observed at several instances. Optimum performance was observed with the membrane having (I)-PVC-TDDMAC1-DOP in the ratio 1:120:1:200 (mg). The sensor works satisfactorily in the concentration range 1.8 x10-5 - 1.0x10-1 M with near Nernstian compliance (52.0 mV per decade of activity) between pH 5.0-9.0 with a fast response time of about 12s. The potentiometric selectivity coefficient values as determined by Fixed Interference Method (FIM) indicate selective response for C104 in presence of interfering ions. The sensor exhibits adequate shelf life (-2 months) with good reproducibility (std. dev. ± 0.4 mV).